Mold Inspection in Vashon, WA

Island homes and moisture

Vashon-Maury Island is a rural, ferry-served part of unincorporated King County, and it holds almost half of the county's shoreline miles. The county's subarea plan calls the housing stock aging, with roughly a fifth of units built in 1939 or earlier, and nearly 90 percent of homes are single-family. Older houses tend to have less insulation, original windows and crawl spaces that were never sealed, and wind-driven rain off the Sound finds every weak spot from fall to spring. About 1.9 percent of island homes are mobile homes, where the area under the floor and the roof seams deserve a careful look.

What to do now

1. Track the smell. Note which rooms, and whether it gets worse after storms or when the heat first comes on.
2. Fix what you can safely reach, such as an overflowing gutter or dripping trap, and dry wet belongings within 24 to 48 hours.
3. Don't paint over stains or seal up growth; the inspector needs to see it.
4. Ask about travel when you book. Some inspectors come from the mainland, so confirm whether ferry time is billed and plan the visit around sailings.
5. Clear access to crawl space hatches, the attic and any outbuildings you want checked.
6. If your parcel is near the shore, look it up on King County iMap's flooding layer so you can tell the inspector whether it sits in a mapped floodplain.

Signs and likely causes

Cost factors

Angi's 2026 national data shows mold inspections typically running $303 to $1,044, and HomeGuide's 2026 national range is $300 to $650. On the island, the price reflects travel, the size of the house and outbuildings, crawl space access and whether samples are needed. If repairs or rebuilding later happen in the coastal floodplain or the island's Sea Level Rise Risk Area, King County Permitting handles building permits, and new or substantially improved buildings there must sit at least 3 feet above base flood elevation.